The episcopate is one; the individual members have each a part, and the parts make up a solid whole. The Church is one; yet by her fruitful increase she is extended far and wide to form a plurality: even as the sun has many rays, but one light; and a tree many boughs but one trunk, whose foundation is the deep-seated root; and as when many streams flow down from one source, though a multitude seems to be poured out from the abundance of the copious supply, yet in the source itself unity is preserved.
(St. Cyprian)